Process and apparatus for making paper



July 11, 1933.

R. c. GERMANSON El AL 1,918,095

PROCESS AND APPARATUS FOR MAKING PAPER Filed Dec. 19. 1932 3 Sheets-Sheet l July 11, 1933. c GERMANSON ET AL 1,918,095

PROCESS AND APPARATUS FOR MAKING PAPER 3 Sheets-Sheet 2 Filed Dec. 19. 1952 Baa oz h C Germanson fiede/z ck Xranfaold y 1933. R. c. GERMANSON ET AL I PROCESS AND APPARATUS FOR MAKING PAPER Filed Dec. 19. 1932 3 Sheets-Sheet 3 $2150, (Vi 5%, PM

Patented July 11, 1933 UNITED STATES PATENT OFFICE RUDOLPH 0. GER-HANSON AND FREDEBLIOK KRANHOLD, OF APPLE-TON, WISCONSIN, AB-

SIGNOB-S TO PAPER PATENTS COMPANY, OF NEENAH,

OF WISCONSIN WISCONSIN, A CORPORATION PROCESS AND APPARATUS FOR MAKING PAPER Application filed December 19, 1982. Serial No. 647,864.

This invention relates to the art of paper then led through the nip of the pressure rolls making, and has reference more particularly to the manufacture of printing papers.

The invention has special value where the finished paper contains a substantial percentage of ground-wood stock,-for example 20% or more. I

Among the objects of the present invention are, to provide an improved paper, to pro vide an improved organized method of and apparatus for making paper having its outer surface treated with a filler or color, and to provide an arrangement which will force the color into the surface stratum of the web, and will obviate the necessity of using smoothing or distributing brushes, bars or rollers and the like.

According to our process, the filler or color is applied during the manufacture of the paper; that is, on the paper machine, preferably after the web has passed over part of the driers, and by the aid of pressure rolls involving the use of considerable pressure. Suflicient pressure is used on the rolls to force the filler into the surface stratum of the web, and to prevent any excess from passing through the nip of the rolls, so that when the Web emerges from the nip the web expands and acts like a sponge to mop up or absorb any filler which may be present, whether on the surface of the web or on the surface of the press roll. This sponging action prevents configuration or streakiness, commonly known as tracks, in the finished surface. \Vhere the rolls are used merely to pick up and apply a coating to the web, these so-called tracks are caused by the excess liquid bridging across between the web and the roll surfaces as the two surfaces begin to diverge, and then breaking down to form irregular deposits of material as the distance between the two surfaces becomes too great for the bridge to span. Hence, the described process, by preventing the formation of tracks, renders unnecessary the use of smoothing devices beyond the surfacing mechanism, and makes practical the use of high speeds. The filler may be applied by one of the pressure rolls, or in certain cases by a traveling felt which is itself impregnated with the filler and with the paper web.

In order that the novel principle of the invention, the manner in which t e same is carried out, and the practical advantages flowing therefrom may be readily understood by persons skilled in the art, we have in the accompanying drawings, illustrated somewhat diagrammatically a machine for treating a paper web on both sides embodying certain novel structural features and operating in accordance with the improved process; and referring thereto;

Fig. 1 is a diagrammatic side elevation of the machine.

Fig. 1a is a diagrammatic View of the calender stack.

Fig. 2 is an enlarged diagrammatic side elevation of the central portion of the machine, including the two coating devices and large drying drums.

Fig. 3 is a side elevation, enlarged, of the left hand filling device shown in Figs. 1 and 2.

Referring to the drawings, the paper web A as it comes from the wet end of the paper making machine, is first passed through a series of drying cylinders 10 and 11 illustrated at the left of Fig. 1, preferably in association with upper and lower felts 12 and 12, respectively, that press the wet web info intimate. contact with the cylinders. From the last cylinder 11 the partly dried web, supported on the upper lap of the felt 13, passes over driven rolls 14 and 15 into the nip of a pair of initial pressure rolls l6 and 17, by which one side is given a dressing of a suitable finishing material, such, for instance, as a water solution of casein or starch with an insoluble inorganic filler, such as china clay, satin White, chalk or other suitable mineral.

From the pressure rolls 16, 17, the web, finished on one side, passes over a large diameter heating drum 18, and thence beneath a heating cylinder 19 and over driven rolls 20 and 21 to and between a similar pair of final pressure rolls 22, 23, by which the dressing is applied to the other side of the web, the latter passing thence over a second large dryin drum 24 and a drying cylinder 25 to a secon substantia-ll vertical series of heating cylinders 26 and 2;, and thence over a horizontal series of heating cylinders 28 and 29 that are practically continuous with the lower end of the verticalseries 26 and 27. The web while traversing the heating cylinders 26, 27, 28 and 29, is preferably pressed into intimate contact with said cylinders by suitably guided felts 30 and 31.

By the first group of drying cylinders the wet web from the paper making machine is sufliciently dried to receive and absorb the first surface filling on one side thereof; b the large dryin drum 18 and cylinder 19 the web is sufficient y dried to receive and absorb the second surface fillin on the other side thereof; and the final rying of the fully treated and finished web is effected by the large drying drum 24 and the cylinders 25, 26, 27, 28 and 29. The described number and grouping of the drying cylinders and drums is merely one which in practice has been found satisfactory, and may be widely varied to suit paper stocks of varying thicknesses and varying characteristics of the filling employed, and other operating conditions.

Describing now the web treating or filling method and instrumentalities, which are best shown in Figs. 2 and 3, we ma here state that the surface filling of the we may be accomplished by the ressure rolls alone, the lower roll dipping into a pan of the filling material and transferring the latter directly to the web, or by the pressure rolls in association with an endless felt which travels through the filling material and is saturated with the latter and then passes between the pressure rolls along with the web. To illustrate both instrumentalities, either of which may be used alone, or both of which may be used, in the same machine, we have shown the latter instrumentality at the left center in Figs. 1 and 2 and in Fig. 3, and the former instrumentality at the right center in Figs. 1 and 2.

Describing first the means for mounting the pressure rolls, equalizing the initial pressure at both ends, and adjusting the working pressure thereof, which are common to both the initial and the final filling e uipments illustrated, the lower pressure r01 such as 17 or 23, di s in a bath 32 of the filling material, whic is contained in a pan 33 carried by and between a pair of yoke members 34, these yoke members being pivoted at 35 to and between a. pair of standards 36 and their free ends being pivoted on horizontal studs 37 carried by collars 38 that, in turn, are slidably mounted on the upper ends of vertical rods 39. Each rod 39 has a ivotal connection 40 to a lower vertical rod 41, to provide for the slight arcuate movement of the free end of the yoke 34. Each rod 41 has threaded engagement with a worm wheel 42 rotatably confined in a gear box 43 mounted on the base 44 of the machine, said base being formed with wells 45 into which the lower ends of the rods 41 may project. Fig. 3 bein a side elevation, shows only one yoke 34 an?! its described supporting means, but it will be understood that identical parts are employed on the oppositeside. Each yoke 34 is formed with a saddle 46 to seat a gudgeon 17 on the end of the pressure roll 17. The collar 38 is formed with a flange 47 that seats on the upper end of a coil spring 48, this latter in turn resting on a washer 49, in turn supported by a nut 50, mounted on a lower threaded portion of the rod 39.

The nuts 50 are used to obtain the same initial compression in the coil springs 48 located on the front and back sides of the press. The pressure and release of the lower roll 17 against its cooperating rolls 16 is effected by turning the worm wheel 42, which raises and lowers the rods 41 and 39, thereby raising the nut 50, which, through the coil spring 48, flange 47 collar 38 and pivot stud 37, exerts a yielding pressure on the free end of yoke 34, the extent of this pressure depending on the extent of rotation imparted to the rod 41. The two rods 41 may be simultaneously rotated by worms 72 on a transverse shaft 74 engaged with the worm wheels 42. This worm gear drive is, of course, self-locking, so that, when the desired pressure between the pressure rolls has been obtained, it is automatically maintained until released.

An arm 51 which may be fast with the collar 38 carries at its free end an arcuate scale 52 over which plays a pointer 53, pivoted at 54 on arm 51, and having a link connection 55 with the washer 49, so that, as the washer is raised and lowered by moving the threaded vertical rod 39 upwardly or downwardly by the worm wheel 42, the degree of pressure is indicated on the scale 52.

A rod mounted on the gear box 43, and

a sleeve 76 mounted on the rod 41 and encircling the rod 45, constitute a safety stop to prevent an excessive travel of rod 41 upward, which, if not stopped, would apply excessive pressure through roll 17 against roll 16.

- Mounted on the standards 36 are curved arms 56 formed with saddles 57 which support the gudgeons 16 of the fixed upper pressure roll 16.

In the lefthand or initial filling equipment for treating the upper or felt side of the web, the filling material 32 is transferred from the pan 33 to the paper web through the intermediary of an endless felt 59 which is of a spongy, resilient character by virtue of which it acts to transfer the filling material in a novel manner and with course, the pressure roll .is picked up by the lower advantageous results as hereinafter described. This felt 59 is trained over suitable rolls such as 60, 61, 62, 63, 64 65, 66, 67 and 68, and a tension roller 69. The felt 59 travels in the direction indicated by the arrows, and from the roll passes into the coatin liquid 32 ]guided by the lower portion 0 the perip cry of the pressure roll 17. During such travel it becomes impregnated and saturated with the filling liquid, the excess of which is first removed by a pressure roll 70 as the felt emer es from the coating pan 33. Above the fe t carrier roll 68 is the paper carrier roll 15 sufliciently spaced from the felt roll 68 to cause the paper and felt to enter the nip of the rolls at a substantial angle to each other, and so positioned that a pool of liquid, P, is formed in advance of the nip and between the felt and the web. As the paper web travels into the nip of the rolls, material from this pool surface of the web, and, as the web and felt emerge from the nip of the rolls, the absorbent web and the spongy felt at once expand and act as sponges to mop up excess filling (if any) on the surface of the web, thus preventing the bridging of the filling material and the spotty or streaky effect on the filled surface of the web hereinabove referred to, and also making unnecessary the employment of smoothing bars, brushes, or rollers to remove the spots or streaks.

In this process it is important that the paper web be brought into intimate contact with the surface of the upper pressure roll 16 before the web enters the pool of filling material at the nip. Otherwise, the filling solution would get between the web and the roll and the paper would be partly filled on that side. Such filling would be very uneven, however, and quite unsatisfactory. Furthermore, the web would probably crush under these conditions. To secure such advance contact, the paper carrier roll 15 is located sufficiently above the felt carrier roll 68 to insure intimate contact of the paper web with the upper pressure roll be fore the web enters the pool P. We have found that if insufiicient pressure is used,the excess filler on the paper will be unevenly removed and the paper will show an uneven finished surface. We have also found experimentally that this process is better suited to the application of light fillings than to the application of heavy fillings.

The filling apparatus illustrated at the ri ht center of Fig. 1, and at the right of Fig. 2, which, in the instance shown, applies the filling to the wire side of the paper web, dilfers from that hereinabove described only in the omission of the felt 59, and, of

70, the filling material being picked up directly b the surface of the lower pressure roll 23 an transferred web engages by the latter directly to the paper web. The web at this point is of the proper dryness to absorb the required quantity of the filling material, the excess filling liquid forming a flood P which trickles back over the advance side of the pressure roll into the an, the retreating side of the pressure roll ing clean and bare of filling material because of the expanding and absorbing action of the compressed web as it emerges from the rolls, and we have found that this latter condition of the retreating side of the lower pressure roll exists also when the spongy felt is used, as in the initial filling equipment, because of the expanding and absorbing action of the compressed felt as it emerges from the rolls; and this condition persists even when the machine is operated at speeds in excess of 400 feet per minute. We have also found that the best results are obtained where the lower pressure roll 17 or 23 is a rubber or rubbersurfaced roll, and the felt band 59 might, of course, be replaced by a peripheral band on the lower pressure roll.

We have referred to the use of a very considerable pressure at the pressure .rolls. Practical tests have shown that a pressure of 200 pounds for each lineal inch of face between the rolls where the felt is used, gives good results. Less pressure may use where the felt is omitted. The amount of the filling is preferably controlled by varying the consistency of the filling mixture.

It will be observed that in the case of both forms of the invention, the web is in intimate contact with the periphery of the upper or dry roll before the ower side of the the pond of filling material. This is accomplished by the use of the carrier roll 15. In this manner the relatively fragile web is adequately supported by the pressure roll before it is subjected to the rather severe ressure incident to its passage through t e nip.

This invention has been found to be particularly satisfactory when using an aqueous mixture containing about 20 to 50% of total solids, said solids comprising 12 to 15% of casein and to 88% of mineral. We have also obtained good results with fillers using modified starches in place of casein. For a base in which the total fibre content consists of 45% of ground-wood and 55% of sulphite, the described process can be carried on at a speed of 450 feet per minute when appl ing to the web a surface filler or dressing of :1 out 6 pounds, i. e. about 5V pounds of mineral per ream of 500 sheets 25 'x 38", and producing a sheet of a total wei ht of 45 pounds per ream. Preferably the ller is made somewhat heavier on the wire side of the web than on the felt side for example, 3 pounds of mineral on the wire side and 2 pounds on the felt side.

The process, as described, is practical for a l in a dressing havin te lidf d?) to about 10 poundi on a side.

Apparentl the cementitious solution sinks into the sur ace stratum to an extent determined by various factors such as the dryness of the web, the amount of round-wood, formation of the sheet, etc. n the other hand the clay or other mineral seems to be collected in more or less spaced areas or nuclei, so that when the sheet is finally calendered, certain portions of the outer fibres are more or less free from mineral. However, there is sufiicient mineral present to fill or partiallv fill the spaces between said outer res. Because of the thinness and the apparent discontinuity of the mineral topdressing, the paper can be finished on the machine without any difliculty.

The paper, although it may carry a total percentage content of mineral (e. g. clay) which is greater than that of an undressed sheet of comparable weight, is much stronger than the undressed sheet. Its ink absorbency is substantially maintained, while its color, irilliancy, opacity and resistance to fading are greatly improved. Two-sidedness is absent, wire and felt marks are eliminated, and neither surface normally will pick or develop a fuzz to any objectionable extent. Because of the fact that parts of the outer fibres of the finished sheet are substantially bare on their exposed surfaces, the sheet as a whole has an ink absorbency value not materially less than that of the undressed sheet. It is an all-purpose printing paper suitable for multi-color, high speed black and white, rotogravure, and offset printing, and can be employed for other urposes.

A paper to have t e above desirable properties should referably carry not more than about 8 poun s of mineral, for the two sides, say 5 pounds on the wire side and 3 pounds on the felt side.

lVe claim:

1. A process of filling a pa or web as part of one continuous paper-ma ing operation, which comprises impregnating a felt with the filling material, passing the felt with the web thereon through pressure rolls under suflicient )ressure to expel part of the filling material mm the felt onto the web and force part of the filling material into a surface stratum of the web, and absorbing excess filling into the felt by the sponging action of the latter as it emerges from the pressure of the pressure rolls.

2. A process of filling a partially dried paper web as part of one continuous papermaking operation, which consists in impregnating a spongy felt with the filling material,

passing the felt through pressure rolls under b sufiiceut pressure to compress the felt and form a pool of filling material on the felt on the entrance side of the nip, propelling the paper web through said pool and the nip a mineral conto fill a surface stratum of the web, and absorbmg excess filling from the filled surface of the web back into the felt by the expanding and mopping action of the latter on the exit side of t e pressure rolls.

3. Apparatus for filling a paper web, including vertically aligned pressure rolls, a pan for filling material, an endless band of absorbent material, means for guiding said band through the filling material to impregnate the'same, means for guidi the impregnated hand through the nip 0 said rolls, means for guiding a paper web through the nip above said band, and means for causing said rolls to engage the web and band under sufiicient pressure to compress the band at the nip and squeeze filling material therefrom into the path of the web on the entrance side of the nip.

4. Apparatus for filling a paper web, including a pan for filling material, vertically aligned pressure rolls the lower of which dips into said pan, an endless band of absorbent material and means for guiding the same around the lower portion of the lower roll and through the filling material to impregnate the same, means for guiding the impregnated hand through the'nip of said rolls, means for guiding a pa r web through the nip above said band, an means for creating suflicient pressure between said rolls to compress the band at the nip and squeeze fillin material therefrom into the path of the web on the entrance side of the nip.

5. Apparatus for filling a paper web, ineluding a pan for filling material, an'u per stationary pressureroll, a lower bodily s liftable pressure roll vertically aligned with said upper roll and dipping into said pan. an endless band of felt and means for guiding the same around the lower portion of said lower roll and through the filling material to saturate the same, a roll for removing excess material from said band, means for guiding the saturated hand through the nip of said pressure rolls, means for guiding a aper web through the nip above said ban and elastic means for adjusting said lower pressure roll bodily toward and from said upper pressure roll.

6. The impovement in the art of making paper which consists in carrying out successively as a art of one continuous papermaking operation, the following steps, namely: forming a web, then conducting said web through the nip of a pair of pressure rolls one of which is wet with an excess of liquid filling material containing a major percentage of mineral and a minor percentage of binder, so as to form a pond of liquid filling material in the entrance to the nip, said rolls eing under such an amount of pressure that as the web leaves the nip, it will absorb any liquid left on the surface of said wet roll so as to leave the treated surface of the web free from traclm, and then drying the sheet.

7. The improvement in the art of making paper, which consists in carrying out successively as a part of one continuous paper makin operation, the following steps, viz orming a web, then conducting sai web through the nip of a pair of pressure rolls, one side only of the web making contact with a pond of liquid filling material in the entrance to the nip of the rolls, the said rolls being under such an amount of pressure that as the web leaves the nip it will absorb any liquid left on the surface of said web, and then applying heat to dry the web, the initial application of heat being cfi'ected before touching said filled side and for a sufiicient length of time so that the filled side during alater stage of drying may be touched without injury.

8. The improvement paper, which consists cessively as a part of in the art of making in carrying out sucone continuous paper makin o eration, the following steps, viz ormlng a web, then conducting said web through the nip of a pair of pressure rolls, with the underside of the web in contact with a pond of liquid filling material carrying a majorpercentage of mineral and a minor percentage of binder in the iii of said rolls, the said rolls being under sucan amount of pressure that as the web leaves the nip it will absorb any liquid passing through the ni and left on the surface of the underside 0 said web, while the filler is prevented from penetrating to the upper side of the web, and then applying heat to dry the web, the initial applicatlon of heat being efiected before touching said filled side and or a suflicient length of time so that the filled side during alater stage of drying may be touched without injury.

9. The improvement in the art of making paper, which consists in carrying out suc cessively as a part of one continuous paper making operation, the following steps, viz :-forming a web, then conducting said web through the nip of a, pair of pressure rolls, only the lower one of which is wet with an excess of liquid filling material carrying a major percentage of mineral and a minor percentage of binder, the said rolls being under such an amount of pressure that the web will absorb substantially all the liquid which the web carries through the nip. and then applying heat to dry the web, the initial application of heat being effected before touching said filled side and for a suflicient length of time so that the filled side during a later stage of drying may be touched without injury.

10. The improvement in the art of making paper, which consists in carrying out successively as a part of one continuous paper making operation, the following steps, namely, forming a web, then conducting said web t rough the nip of a pair of pressure the lower one of which is wet with an excess of liquid filling material so as to form a pond in the entrance to the ni of said rolls, the said rolls being under suc an amount of pressure that as the web leaves the nip it will absorb any liquid on the exit surface of said wet roll, and then applying heat to dry the web, .the initial application of heat being effected before touching sai filled side and for a sufiicient length of time so that the filled side during a later stage of drying may be touched without injury.

11. The improvement in the art of making paper, which consists in carrying out successively as a art of one continuous paper making operation, the following steps, namely, forming a web, partially drying the same, then conducting the partially dried web through the nip of a pair of pressure rolls, the lower one of which is wet with an excess of liquid filling material so as to form a pond in the nip of said rolls, the said rolls being under such an amount of pressure that as the web leaves the nip it will absorb any l i uid carried through the nipl by the web, and en applying heat to dry t e web, the initial a p ication of heat being eflected before touc ing said filled side an for a suflicient length of time so that the filled side duringa later stage of drying may be touched wit out inury.

12. An organized paper making machine for continuous operation comprising means for forming a web and removing a portion of the moisture from said web, a air of pressure rolls, means for conducting t e web from the forming and moisture removing means into the nip of said pressure rolls, means for conducting an excess of liquid filling material into the nip and under said web as the latter enters said nip, so as to form a pond in the nip of said rolls, means for subjecting said rolls to suflicient pressure to incorporate into the under side of the web a portion of the said filler while preventing any of the excess from accumulating on said web, and a plurality of drying cylinders for applying heat to said web after the latter leaves the nip of the pressure rolls, one of said drying cylinders being arrange to receive the web from said pressure rolls with the treated side outwardly, and another drying cylinder being arran ed to receive said web from said first cylin er so that the filled side of said web is in contact with said second cylinder, the circumferential len h of said first cylinder being sufiicient to ry said filled side sufliciently to prevent injury of said filled side when the latter engages the surface of said second cylinder.

13. In a continuous organized machine for paper making, the combination of web-forming means, a pair of instrumentalities for applying rolls,

filler successively to opposite sldes of the web, each instrumentality comprising a. pair of pressure rolls through the nip of inders and means for rotating said linden-s which the web is passed means for supplyin oppbsite directions, one of said i cyling to the entrance to the nip of each palr, inders serving to dry the sheet as u and under the web, liquid filler in quantity 5 suflicient to form a pond between the rolls in en amount sufiicient to prevent excess filler nip and to intimately 1) face stratum of the travels between in the entrance to e nip, and means for supplying pressure the sheet after filling instrumentality,

arranged to receive and upper surface of the cy surface of the sheet presented upwardly.

the latter leaves from passing through the incorporate into the surweb substantially all of the liquid carried through the nip by the web,

the pa r passing through said nips succes- RUDOLPH C. GERMANSON. sively opposite directions, two drying cyl- FREDERICK KRANHOLD.

Dl 8O LAI M E R 1,918,095.-Rudolph C. Germs/man and Frederick Kmnhold, Ap ton, Wis. Pnoons min Armm'rus FOR MAKING Perms. Patent ted July 11, 1933.

Disclaimer filed December 26, 1935, by the sssignee, Paper Patents Gummy.

Hereby enters the following disclaimers:

1. from the scope of claim 1 of said pressure between the rolls is insuflicient to produce cation:

2. Disclaims from the scope of claim 3 apply ressure suficient to produce the result [Qificial Gazette January 81, 1986.]

atentsnyprocessinwhichthe eresult set forthinthespecifiany a psrstus which is not sdspted to set orth in the tion.

d l h Isaial 7 an tieot ercyin er ingto each cylin being dryihesbeetonthe der with the wet a. pair of pressure rolls through the nip of inders and means for rotating said linden-s which the web is passed means for supplyin oppbsite directions, one of said i cyling to the entrance to the nip of each palr, inders serving to dry the sheet as u and under the web, liquid filler in quantity 5 suflicient to form a pond between the rolls in en amount sufiicient to prevent excess filler nip and to intimately 1) face stratum of the travels between in the entrance to e nip, and means for supplying pressure the sheet after filling instrumentality,

arranged to receive and upper surface of the cy surface of the sheet presented upwardly.

the latter leaves from passing through the incorporate into the surweb substantially all of the liquid carried through the nip by the web,

the pa r passing through said nips succes- RUDOLPH C. GERMANSON. sively opposite directions, two drying cyl- FREDERICK KRANHOLD.

Dl 8O LAI M E R 1,918,095.-Rudolph C. Germs/man and Frederick Kmnhold, Ap ton, Wis. Pnoons min Armm'rus FOR MAKING Perms. Patent ted July 11, 1933.

Disclaimer filed December 26, 1935, by the sssignee, Paper Patents Gummy.

Hereby enters the following disclaimers:

1. from the scope of claim 1 of said pressure between the rolls is insuflicient to produce cation:

2. Disclaims from the scope of claim 3 apply ressure suficient to produce the result [Qificial Gazette January 81, 1986.]

atentsnyprocessinwhichthe eresult set forthinthespecifiany a psrstus which is not sdspted to set orth in the tion.

d l h Isaial 7 an tieot ercyin er ingto each cylin being dryihesbeetonthe der with the wet 

